Room temperature hydrogen gas sensor based on nanocrystalline SnO2 thin film using sol-gel spin coating technique

High-quality nanocrystalline (NC) SnO2 thin film was grown on SiO2/Si substrate by sol-gel spin coating technique at low temperature. X-ray diffraction and field emission scanning electron microscopy results observed the high quality of the produced NC SnO2 thin film. A metal-semiconductor-metal (MSM) H-2 gas sensor was fabricated utilizing palladium (Pd) metal and NC SnO2 thin film. Hydrogen (H-2) sensing capabilities of the NC SnO2 thin film were examined at room temperature (RT), and the sensitivity was 600 % in the presence of 1000 ppm of H-2. The sensing measurements for H-2 gas at different temperatures (RT to 125 A degrees C) were repeatable for over 50 min. The sensor showed a sensitivity of 1950 % at 125 A degrees C upon exposure to 1000 ppm of H-2. A significant variation in the sensitivity of the NC SnO2 thin film sensor was noticed at different concentrations of H-2 at different operating temperatures. These high sensitivities are attributed to the increase in adsorption/desorption of gas molecules, which were achieved by increasing the porosity of the NC SnO2 thin film surface by adding glycerin to the sol solution. The high sensitivity of this H-2 gas sensor at RT indicated that it has the capability to be used as a portable RT gas sensor.